Man pages matching name xmvacreatemanagednotebook in section 3:

XmVaCreateManagedNotebook.3.en	debian 10 / libmotif-dev
XmVaCreateManagedNotebook.3.en	debian 11 / libmotif-dev
XmVaCreateManagedNotebook.3.en	debian 12 / libmotif-dev